1. Field of Invention
The present invention relates to an ozone laundry system and its method of use with continuous batch or tunnel washers. More particularly, it relates to an ozone laundry system and its method of use with continuous batch or tunnel washers wherein ozone can be injected into a plurality of different chambers along the continuous batch or tunnel washer and wherein the interfacing of a plurality of system controls occurs on a centralized HMI controller along with DOM and ORP monitoring.
2. Description of the Prior Art
Continuous Batch Washers (CBWs), also known as Tunnel Washers, are well known in the prior art. These machines are designed as industrial laundry machines for handling heavy wash loads. They are used largely by hotels, resorts, hospitals and high-volume commercial laundry service companies wherein a constant wash cycle may run as much as 24 hours a day. CBWs typically include a long metal tube that is called the “tunnel.” A huge metal spiral called an “Archimedes Screw” runs down the center of the tunnel, dividing it into sections called “pockets” or “chambers.” As the screw rotates, linen is forced from one end of the tunnel to the other. The screw typically employs a porous metal so that the laundry can move through the washer in one direction while water and chemicals are forced through the screw and hence the chambers in the opposed direction. As such, the linen moves through pockets of progressively cleaner water and fresher chemicals. Dirty or soiled linen is continuously placed into one end of the tunnel while clean linen is continuously moved out of the other end.
As with all industrial laundry services and machines, the use of certain chemicals that are harmful to the environment has necessitated that these machines either capture the chemicals for proper storage and disposal or that they be configured to use less chemicals. However, in certain scenarios, especially in hospitals and in hotels, the laundry being used must be washed to a certain degree of cleanliness, since many different people will use the laundered items from one wash to the next. This degree of cleanliness can usually only be achieved through the use of harsh chemicals that ensure that the soiled laundry will not only be cleaned but also whitened in the case of white linen items (i.e., bedding and bath towels).
Due to this laundry need, improvements to CBWs have been employed over the last few years wherein ozone [or trioxygen (O3), a triatomic molecule, consisting of three oxygen atoms) is injected into a chamber of the CBW or tunnel washer to replace one or more of the harsh cleansers used in such laundry systems. However, the use of ozone presents its own set of problems as ozone is known to be unstable and at ground levels can be harmful to the respiratory system of animals, which of course includes the humans operating these CBW and tunnel washer systems. Therefore, great care must be taken in the control and use of ozone in any laundry system. Further, dissolved ozone in a laundry system, such as a CBW or tunnel washer, can not simply be disposed of into the sewer system. It must be properly contained, destroyed or disposed of in a manner consistent with environmental laws and regulations.
The use of ozone to disinfect laundry is actually very well known in the prior art as Great Britain Patent No. 3371 to Otto discloses a process and apparatus for disinfecting linen and other fabrics by a combined action of ozone and steam. However, it does not disclose or suggest to the use of ozone in a multi-chambered laundry system such as with a CBW or tunnel washer. Canadian Patent No. 2310864 to Erickson et al. discloses a small laundry ozonation system for home use wherein venturi-type differential pressure injectors are used for injecting ozone into the water passing from a water supply to the washing machine. This prior art invention too fails to disclose or suggest to the use of ozone in a multi-chambered laundry system such as with a CBW or tunnel washer, but it does disclose that the ozone can be entrained along a water line by injectors.
For use in a large commercial laundry system, U.S. Pat. No. 5,493,743 to Schneider et al. discloses an ozone assisted laundry wash process and apparatus, which employs a venturi-type injector for entraining ozone into the water of storage and/or contact tanks of the washing system. This prior art system also includes contact extenders, static mixers and flow restriction fittings, which all work to collect, filter and reuse the ozonated water to assist in waste water disposal problems. However, the storage and/or contact tanks make this system less than ideal for large commercial use as it is difficult to retrofit to an existing CBW or other tunnel washer and it does not allow for independent control of system chamber injection of the ozone.
U.S. Pat. No. 6,254,838 to Goede discloses an ozone generating system for laundry systems wherein a predetermined amount of ozone is dissolved in the water with a minimum of entrained ozone. This prior art system includes the use of an entrained gas separator assembly in series with re-circulating plumbing that feeds and discharges ozone enriched water. The entrained gas separator assembly allows the water with dissolved ozone to pass through while extracting the entrained ozone for subsequent use or destruction. The entrained gas separator includes a secondary tank with an off-gas valve for releasing the entrained gases including ozone. The ozone rich water from the tank's outlet is passed through a water conditioner prior to being delivered for use. In this reference, separate tank configurations are used to dissolve the entrained ozone in the water. Here again we see the inefficient use of gas separators and storage tanks that make it difficult to retrofit this system to an existing CBW or other tunnel washer and complicates tunnel washers overall by the use of storage. Also, as in the other prior art systems, this invention fails to disclose or suggest the use of system chamber specific injection of ozone as well as monitoring of each specifically injected chamber for determining critical aspects of an ozone laundry system such as dissolved ozone (DOM) and oxidation reduction potential (ORP).
US Patent Appl. No. 20080302139 to Zorn discloses an ozone laundry system wherein a tunnel washer system generates ozone (in excess) and then dissolves the ozone in water at various stages along the tunnel washer, such as with a venturi injector. In its preferred embodiment, it dissolves the ozone into three stages or compartments of the tunnel washer. However, this reference employs a storage tank, from which an ozone destruct mechanism is employed so that excess ozone can be de-gassed and subsequently destroyed. The need for this rises from the over oxygenated re-circulated water used in this system. This is a serious limitation as this invention is incapable of having independent control and monitoring of exact entrained ozone at each injection point. Therefore, the actual ozone production can not be adjusted independently by the ozone demand required to ozonate the fresh water supply at such location to a preset dissolved ozone level. Over oxygenated water can not be avoided in this prior art system and therefore it requires storage tanks, transfer pumps, cooling systems, ozone exhaust, ozone destruct systems, ozone gas-separators and other like machinery that make this prior art system inefficient, difficult to operate and very expensive to install and operate.
Oxidation reduction potential (ORP) measurement is the measuring of oxidation occurring in any chemical. In some prior art ozone laundry systems ORP measurement is employed to determine the oxidation level of the water in a tunnel washer at the beginning of the wash cycle and is used for recording purposes only. However, nowhere in the prior art are there any ozone laundry systems that measure ORP in the press pan at the end of the tunnel washer to provide a post process validation based upon a previously established ORP baseline. Further, no prior art system is using the ORP readings for diagnostic and verification purposes, of which such readings is directed to an HMI (Human Machine Interface) for reporting, alarm notification, control and reset capabilities. Further, nowhere in the prior art can you find an HMI controller on an ozone laundry system that combines sensor reporting, system alarm and system control all in a compact user interfaced touchscreen monitor that is integrated with the ozone generator system of which can be remotely controlled through the Internet or any intranet. This is a serious limitation to all exiting ozone laundry systems that needs improvement.
In view of what is known in the prior art, it can be clearly seen that vast improvements are needed in ozone laundry systems for use as retrofitted systems or to be part of a complete new installed system for CBWs and tunnel washers in the commercial arena that incorporates enhanced sensor and control capabilities that can all be controlled from a centrally located HMI controller on a cabinet that incorporates the entire ozone generator and distribution system and wherein specifically dissolved ozone can be deposited in particular chambers of the tunnel washer by entraining ozone through injectors along independent water entry points.